There are plenty of reasons to reject factory farming, but in the case of beef, your carbon footprint shouldn’t be one of them. According to EcoWatch, new research shows that grazed cattle provide an outsized contribution to greenhouse gasses, as opposed to cattle kept largely indoors and fed on grain.

The report [PDF], released by Oxford’s Food Climate Research Network, aims to provide definitive answers to what has been a heavily debated topic in environmental circles. Some research has found that grazing cattle actually reduces the carbon footprints of beef operations, because all that pasture stores carbon and prevents it from being released into the atmosphere, and because all that chomping stimulates new vegetation growth. Other research has found that the benefits aren’t as great as the grass-fed boosters estimate—especially since the fields of grain used to grow cattle feed for factory farms sequester carbon, too.

The new Oxford research comes down firmly on the side of the latter camp. It finds that while grass-fed operations can help sequester carbon, it’s “only under very specific conditions,” in part since the definition of what a grassland is can vary wildly. There are natural ranges dominated by wild vegetation, there are pastures that are actively maintained and managed by farmers, and there is land that lies somewhere in between. Overgrazing, trampling, and soil conditions can all negatively impact how much carbon the grasses can sequester. And even under the best conditions, the gains can be short-lived. “This sequestering of carbon is even then small, time-limited, reversible, and substantially outweighed by the greenhouse gas emissions these grazing animals generate,” according to FCRN.

And it seems that even if the vegetation does sequester carbon, grass-fed beef is still an outsized source of greenhouse gasses.

To begin with, all cattle are a huge drain on the environment, no matter how you feed them. The report estimates that the livestock supply chain generates around 14.5 percent of global greenhouse gas emissions, and cattle create 65 percent of those livestock emissions. But even compared to cattle in general, grass-fed animals are heavy polluters. Within the global protein supply, grass-fed beef makes up around 1 gram of protein per person, per day, compared to 13 grams from all ruminants (cattle, sheep, goats, etc.). But these grazed cattle generate up to a third of all global greenhouse emissions from ruminants. In other words, grass-eating cattle create an outsized cost—emissions-wise—compared to the meat they provide.

And the carbon sequestration doesn't help enough to offset that. The report estimates that the carbon sequestration that might occur from grazing practices would only offset emissions by 20 percent.

There are other reasons to buy grass-fed beef, of course, whether it’s about ethical concerns with factory farming or just a taste preference. But if you’re going to choose grass-fed, your reason shouldn’t be concern for the environment.

[h/t EcoWatch]